Technical Abstract:
Chromium (Cr) supplementation alleviates the metabolic syndrome, glucose intolerance, depression, excess body fat, and type 2 diabetes. However, not all studies have reported beneficial effects of Cr. Molecular evidence is lacking on the effects of Cr. The objective of this study was to investigate the effects of Cr on gene regulation in rats with a high-fructose diet-induced metabolic syndrome. Wistar rats (10 per group) received a fructose-rich diet (FD) or FD plus 2 g Cr:-histidine or 500 mg Cr:-picolinate/kg diet for 8 weeks. Quantitative real-time PCR was used to evaluate Cr effects on the expression of genes coding for the glucose transporter (GLUT) family, insulin-signaling components, adipokines, pro-inflammatory cytokines, and anti-inflammatory tristetraprolin (TTP) family in the brain, kidney, liver, and muscle. Among the significant results were that many genes were down-regulated by Cr treatments. Among those down-regulated genes in the brain include GLUT4, INSR, IRS2, GRB2, PIK3R1, SOS1, IGF1R, IGF2R, TAU, and ZFP36L1. The expression of TTP, VEGFB, INSR, and PIK3R1 was significantly reduced in the kidney. Genes with reduced mRNA levels in the liver included TTP, VEGF, GLUT2, GLUT4, INSR, PIK3CB, PIK3R1, GRB2, IGF1R, IGF2R, and HuR. No significant effects were observed in the muscle. These data demonstrate that the brain, liver, and kidney may be more sensitive to Cr than the muscle.